M Series Multiservice Routers can be deployed in both high-end enterprise and service-provider environments.

T Series Core Routers is ideal for service provider environments and is deployed within the core of those networks.

J Series Services Routers are deployed at a branch and remote locations in the network.

MX Series Ethernet Services Routers is targeted for dense dedicated access aggregation and provide edge services in medium and large POPs.

EX Series Ethernet Switches are designed for access, aggregation, and core deployments and are well for enterprise and data center.

SRX Series Services Gateways is designed to meet the network and security in both enterprise and service provider environments.

The Junos OS is compartmentalized into multiple software processes. Each process runs in its own protected memory space, ensuring that one process cannot directly interfere with another. This modularity also ensures that new features can be added with less likelihood of breaking current functionality are some advantages of the Junos OS.

The primary functions of the control plane are to maintain routing intelligence, control and monitor the chassis, and manage the Packet Forwarding Engine (PFE). The primary functions of the forwarding plane are to forward packets and to implement advanced services.

Transit traffic is forwarded through the PFE on platforms running the Junos OS, based on the forwarding table installed on the PFE. Exception traffic is processed locally by the platform running the Junos OS by either the PFE or the RE depending on the type of traffic. Host-bound packets, such as protocol and management traffic, are passed directly to the RE for processing, while traffic requiring ICMP error message responses is typically handled by the PFE.

> ?

> clear ?

> help topic interfaces ?

> help topic interfaces address

> help reference interfaces address

edit - functions like a CD command

up - moves up one level

up n - moves up n levels

top - moves to the top of the hierarchy

exit - moves to the previous, higher level in the hierarchy or exits configuration mode if at the top level of the hierarchy

Two primary modes exist within the Junos OS: the operational mode and the configuration mode. A third mode also exists in the form of the FreeBSD shell.Type configure at the operational mode prompt to enter configuration mode which allows to make configuration changes.

Use the operational mode to monitor and troubleshoot the software, network connectivity, and hardware. Use the configuration mode to configure a device running the Junos OS, including interfaces, protocols, user access, and system hardware.

Use the Spacebar to complete a command and the Tab key to complete a variable.

The top command is the quickest method of returning to the top of the hierarchy.

The active configuration has been committed and is in use, whereas the candidate configuration is not active until performing a commit operation.

The show | compare command displays the differences between the currently active and candidate configurations.

The Routing Engine is the intelligence of the router. It operates the routing protocols and builds a routing and forwarding table. The forwarding table is copied to the Packet Forwarding Engine, where the actual transmission of user data packets is handled.

The JUNOS software is stored on the internal flash drive, the internal hard drive, and the removable flash media. When the router begins to boot, the removable media is checked first, followed by the internal flash drive, and finally the internal hard drive.

May save the router's configuration to the hard drive with the save command. The load command restores files to the candidate configuration. The candidate configuration becomes the active configuration with the commit command. Can easily return to a previous configuration with the rollback command.

There are four main ASICs used in the Packet Forwarding Engine: the Internet Processor ASIC, the Distributed Buffer Manager ASIC, the I/O Manager ASIC, and the PIC I/O Manager ASIC.

A packet is received on an interface (1,2) and is segmented into J-cells by the I/O Manager ASIC (3). The Distributed Buffer Manager ASIC stores the packet in the shared memory pool (4-6). The Internet Processor ASIC performs a route lookup (7) and sends the result to the Distributed Buffer Manager ASIC (8), which forwards it to the outgoing I/O Manager ASIC (9). After queuing the packet, the I/O Manager ASIC receives the J-cells from the memory pool (10) and re-forms the packet (11). It is sent to the outgoing PIC I/O Manager ASIC for transmission into the network (12).

An exception packet could be a routing protocol update, a locally addressed packet, or a packet requiring the generation of an ICMP error message. The CPU on the router's control board handles these exception packets and performs the appropriate action.

Operates routing protocols, loads the JUNOS software, and controls the CLI are the functions of the Routing Engine.The Routing Engine performs multiple functions, including operating the routing protocols on the router, loading the JUNOS software, and controlling the CLI. The Packet Forwarding Engine controls packet forwarding.

Routing Engine router component is responsible for creating the forwarding table.The Routing Engine builds the master routing table, selects the best path to each route, and places those next hops into the forwarding table.

The PIC I/O Manager ASIC is responsible for transmitting packets function.The PIC I/O Manager ASIC is responsible for receiving and transmitting data packets from the physical media connected to the PIC.

The Internet Processor ASIC is responsible for performing route lookups function.The Internet Processor ASIC consults the forwarding table on the control board to determine the next-hop router along the path to the destination.

The I/O Manager ASIC is responsible for creating J-cells function.The I/O manager ASIC is responsible for multiple functions in the router. One of those is the creation of J-cells from the original data packet.

The Distributed Buffer Manager ASIC is responsible for storing packets in memory function.The primary role of the Distributed Buffer Manager ASIC is storing and retrieving J-cells from the packet storage buffer.

A unicast packet is flowing through the Packet Forwarding Engine. Incoming I/O Manager ASIC receives the packet after the incoming PIC I/O Manager ASIC performs its functions.After receiving the packet from the physical media and performing any link-layer functions, the incoming PIC I/O Manager ASIC sends the packet to the incoming I/O Manager ASIC on its FPC.

Switching control board CPU component of the router is responsible for handling exception packets.The CPU on the router's control board is responsible for handing exception packets. Some of those exception packets might reach the Routing Engine.

IP packets with TTL=1 and Routing protocol updates are considered exception packets.Routing protocol updates and packets requiring an ICMP error message (TTL=1) are considered exception packets. A Juniper Networks router does not communicate using the HTTP or SMTP protocols. Therefore, these packets must be transiting the router and are handled by the Packet Forwarding Engine.

mgd JUNOS software daemon is responsible for operating the CLI.The Management Daemon (mgd) is responsible for controlling the CLI process.

rpd JUNOS software daemon is responsible for controlling the routing protocols.The Routing Protocol Daemon (rpd) is responsible for all routing protocol activity on the router.

When issued from the top of the configuration hierarchy, save saved-file command creates a file called saved-file that contains the entire candidate configuration.The save command takes portions of the candidate configuration and places them in a file you specify. When used from the top of the hierarchy, this process saves the entire candidate configuration.

rollback 5 command places the juniper.conf.5.gz file in the candidate configuration.load override juniper.conf.5.gz and load merge juniper.conf.5.gz will look for the juniper.conf.5.gz file in the user's home directory, where it is not stored by default.

/var/home is the router store each user's home directory.Each user configured on the router receives his or her own home directory in the /var/home section of the hard drive.

Internal flash drive is the primary boot media for the JUNOS software.The router's internal flash drive is the primary boot location for the JUNOS software.

Internal hard drive is the secondary boot media for the JUNOS software.The router's internal hard drive is the secondary boot location for the JUNOS software.

request system software add filename command loads a new version of the JUNOS software into the internal flash drive.The request system software add filename command loads a copy of the JUNOS software onto the router's flash drive.

Ctrl+A Emacs keystroke takes the cursor to the beginning of the command line.To reach the beginning of the command line, use the Ctrl+A keystroke. Ctrl+E takes you to the end and Ctrl+W deletes the previous word. Ctrl+D closes your terminal during a load merge terminal operation.

load merge terminal command allows you to paste text directly into the candidate configuration.The load merge terminal command allows you to cut and paste configuration directly into the router.

When committing configuration, commit confirmed command allows the router to automatically return to a previous configuration.The commit confirmed command allows the router to return to the previous configuration automatically if don't issue a regular commit within the default 10-minute timer.

The format consists of a two-character media type designator followed by the FPC slot number, the PIC slot number within an FPC, the port number on the PIC, and the logical unit. the format is media_type-fpc/pic/port.unit.

Each Juniper Networks router contains the fxp0 and fxp1 permanent interfaces. All interfaces contained on a PIC are considered transient because they can be removed at any time.

The inet, inet6, iso, and mpls protocol families are configurable on a Juniper Networks interface.

Each interface in the JUNOS software requires some logical properties. These often include the Layer 3 and Layer 2 addressing information for enabling proper network operation.

The show interfaces extensive command, information such as the current status, input/output byte and packet statistics, and input/output error counters are available in the command output.

Both loopback and BERT testing help to locate trouble spots on a physical network circuit.

Type, FPC, PIC, and port is the order of elements in the JUNOS software interface naming convention.The order is the media type, FPC slot number, PIC slot number, and PIC port number.

0 through 7, left to right are the FPC slot numbers for an M40e numbered.An M40e has eight vertical FPC slots. They are numbered 0 through 7, left to right.

0 through 3, right to left are the PIC slots numbered on an M20 FPC.An M20 has four PIC slots in each FPC. Since the FPC has a horizontal orientation, the PIC slots are numbered 0 through 3, right to left.

Permanent and transient are two different types of interfaces on a Juniper Networks router.Juniper Networks routers have two types of interfaces: permanent and transient.

Keepalives, Description, and FCS are the example of a physical interface configuration.Only the protocol address is a logical property of an interface.

DLCIs number and Protocol MTU are both examples of a logical interface configuration properties.Scrambling and description are physical properties.

The router assigns a /32 prefix length to an IPv4 address if you do not specify one in the configuration.In the absence of a prefix length, the router assumes a 32-bit prefix length for an IPv4 address.

show interfaces so-* terse command displays the status of all SONET interfaces on the router.An asterisk ( * ) may be used as a wildcard character. The command show interface so-* terse will display the status of all SONET interfaces on the router.

An interface has multiple IP addresses configured. The interface's primary address is the lowest numbered address on the interface.An interface contains only a single primary address and, by default, it is the lowest numerical prefix on the interface.

The configuration is ignored and not applied is the result of using the deactivate command.When an interface has been deactivated, the interface is marked inactive and the configuration statements are ignored when the candidate configuration is committed.

In the show interfaces extensive output, Input Errors field displays framing errors.Input Errors are the sum of the incoming frame aborts and FCS errors.

input L3 incompletes field in the show interfaces extensive output displays received packets with a damaged IP header.The input L3 incompletes field is a counter that is incremented when the incoming packet fails Layer 3 (usually IPv4) checks of the header.

A Frame Relay interface is configured to support DLCI values 40, 50, and 60. Incoming frames show a DLCI 45 at input L2 channel errors field in the show interfaces extensive output.The input L2 channel errors field is a counter that increments when the software cannot find a valid logical interface for an incoming frame.

99.0.0.0/17 *[Static/5] 00:00:06 > to 10.0.0.6 via ge-0/0/1.099.0.0.0/19 *[Static/5] 00:01:05 > to 10.2.0.10 via ge-0/0/2.099.0.0.0/24 *[Static/5] 00:01:05 > to 10.2.0.14 via ge-0/0/3.099.0.0.0/26 *[Static/5] 00:01:05 > to 10.2.0.18 via ge-0/0/6.0There are four static routes that route traffic through different interfaces.ge-0/0/6 interface does the router use if traffic is sent to the 99.0.0.1 destination

14 host addresses are available in the 172.27.0.0/28 network

Benefits of using IPv6:

Supports a greater level of security by integrating features that were optional add-ons in IPv4

OSPF hello packets that are sent from a remote router and are destined for the local router and Telnet traffic that is sent from a remote host and is destined for the local router are two examples of RE exception traffic.

A BGP router only uses the MED attribute, by default, when multiple routes in the Adjacency-RIB-In table have arrived from the same neighbouring AS.

By default, a Response message carries 25 route entries. When plain-text authentication is configured, one route entry is used to store the authentication data. Therefore, only 24 route entries can be advertised in this scenario. Using MD5 authentication, however, requires the use of two route entries, leaving a capacity of 23 RIP routes in the message.

ge-4/3/2:

media type Gigabit Ethernet interface in slot 4 in the chassis/slot 3 of the FPC/port 2 in a PIC.

media type Gigabit Ethernet interface on FPC 4/PIC 3/Port 2.

RIPv2 defaults to advertising Response messages using the 224.0.0.9/32 multicast group address.

The JUNOS software places a single next-hop entry into the forwarding table for each valid route in the routing table, by default. Can modify this behaviour by configuring a routing policy within the [edit routing-options forwarding-table] configuration hierarchy.

3 prefixes will match route-filter 192.168.0.0/16 upto /17. The upto match type stops the evaluation of the route filter and matches the routes found at the specified level. This route filter matches the 192.168.0.0/16, 192.168.0.0/17, and 192.168.128.0/17 routes.

The Routing Protocol Daemon (rpd) software process is responsible for / in charge of operating all routing protocols in the JUNOS software.

Use commit check to confirm syntax:[edit]user@host# commit check[edit interfaces ge-0/0/10 unit 0] 'family' When an ethernet-switching family is configured on an interface, no other family type can be configured on the same interface.error: configuration check-out failed

Use show | compare rollback x to display differences in rollback configurations

Remember to check all devices that could introduce a problem

Eliminate the control plane as a possibility before focusing on the data plane

When configuration errors are suspected, it is OK to quickly glance at configuration, but rely on operational mode commands to isolate errors:

The human brain sees what it expects to see

The Human Brain, a Funny Thing...:

Take a moment and read the following paragraph:

Arocdnicg to rsceearch it deosn’t mttaer in waht oredr the ltteers in a wrod are, the olny iprmoatnt tihng is taht the frist and lsat ltteer are in the rghit pcale. The rset can be a toatl mses and you can sitll raed it wouthit pobelrm. Tihs is buseace the huamn mnid deos not raed ervey lteter by istlef, but the wrod as a wlohe.

Generally eliminate hardware as a possibility before progressing on to software

The Human Brain - Still a Funny Thing...:

Count the number of Fs:

The necessity of training farm hands for first class farms in the fatherly handling of farm live stock is foremost in the eyes of farm owners. Since the forefathers of the farm owners trained the farm hands for first class farms in the fatherly handling of farm livestock, the farm owners feel they should carry on with the family tradition of training farm hands of first class farmers in the fatherly handling of farm live stock because they believe it is the basis of good fundamental farm management.

Change the root password to lab123 by issuing the set system root-authentication plain-text-password command.

Issue the show system storage command to determine the amount of storage space available on your router.User home directories are located at /var/home. The /var directory is mounted on a partition of ada1s1f, so it is currently being used to store user home directories.

Enter the shell as the root user by issuing the start shell user root command. Enter the password of lab123 when prompted.

Perform a read-only test to determine the integrity of the ada1 storage drive. Use the dd if=/dev/ada1 of=/dev/null bs=1m command to perform the test.It might take between 5 or 10 minutes for the test to complete. Be patient.

If the test results show that errors occurred, please notify your support because your router might be experiencing a hardware failure.

Direct your router to reboot in 20 minutes using the request system reboot in 20 command.Shutdown at Tue Jan 16 09:58:54 2018.The router will reboot at 09:58.

Clear the schedule reboot using the clear system reboot command.

Direct your router to reboot immediately using the request system reboot command.

View the boot messages that occurred during the reboot process by issuing the show system boot-messages | no-more command.The boot messages record the step-by-step process that the RE goes through to boot. No critical errors should have occurred. You may see a few instances while the system is coming online.

Use the show system uptime command to determine the router's current time and date.Current time: 2018-01-16 09:53:28 ICTThe time and date are currently 2018-01-16 09:53:28 ICT.

View the messages log file using the show log messages to view detailed information about the PFE during the reboot that just occurred. It might be helpful to use the match modifier to ensure that only entries from today's date are shown. For example, if today's date is Jan 16th, issue the command show log messages | match "Jan 16" (you might need to use two spaces between month and day).

You might notice that matching on the date might not narrow the search down enough because thousands of entries might happen on any one day. Use the previous command but add a second pipe that matches on reboot, show log messages | match "Jan 16" | match reboot.

Using the show log messages | match chassisd | match fpc | match online command, determine the exact time that FPC 0 came back online after the reboot. (Status of FPCs are tracked by chassisd.)

Monitoring Chassis Alarms:

Determine if any alarms exist by issuing the show chassis alarms command.2 alarms currently active2 active alarms exist.

Enter configuration mode and change the default chassis alarm settings such that if any Ethernet ports are in the link-down state issuing set chassis alarm ethernet link-down red, the router will generate a red alarm.

Shows that user lab is logged in from the IP address of 192.168.0.231.

Forcibly remove the instance of user by issuing the request system logout user lab terminal pts/0.

Issue the show system processes extensive command.

The chassisd daemon manages the chassis components of the router.

The rpd daemon manages the routing function.

Issue the show route command.

10.85.0.12/32 *[Direct/0] 16w3d 20:52:27Shows that the oldest route has been in the routing table for 16w3d 20:52:27.

If for some reason the rpd process were to restart, the Junos OS removes all routing information from the routing table. Then, the Junos OS adds any current routing information through independent and dynamic routing protocols.

Issue the restart routing command.

All the routes in the routing table were removed and replaced with new routes, which you can see by viewing the current age of the routes in the routing table.

Restarting rpd causes ISIS to completely reconverge. All neighbor adjacencies must re-establish, the router must repopulate the linkstate database, and calculations must run on all possible routes to determine the best path.

You can restart only ISIS by deactivate protocols isis command in the [edit] hierarchy level, committing the configuration, activate protocols isis, and committing the configuration again.

Generating Core Files:

Issue the show system core-dumps command:/var/crash/*core*: No such file or directory/var/tmp/*core*: No such file or directoryNo core dump files are present on your device.

Generate a core dump file using the rpd process, request system core-dump routing.

An autonomous system mismatch exists between your device and the ISP-1 router.

Should change the peer-as value to 65001.

Now that we know what the problem is, should remove the traceoptions configuration that recently configured.delete traceoptionsfile list /var/log/ | match tracefile delete /var/log/bgp-trace.log

Determine Current Control Plane Requirements:

Review the current system configuration using the show system command.FTP, SSH, Telnet, and NTP traffic must be allowed by a control plane protection filter.

Review protocol configuration using the show protocols command.Also BGP and ISIS must be allowed to maintain the current communication requirements.

Issue the show isis adjacency command to verify ISIS is working correctly.

Issue the show ntp associations command to review the current status of NTP.

Configuring Control Plane Protection:

Navigate to the [edit policy-options] and create a prefix list named bgp-neighbors. Use the apply-path feature to walk through the Junos configuration to discover all the BGP neighbors within the configuration.set prefix-list bgp-neighbors apply-path "protocols bgp group <*> neighbor <*>"

Create a prefix-list named ospf to match both of the well-known multicast addresses (224.0.0.5/32 and 224.0.0.6/32) as well as the network associated with the WAN link. This solution does not scale well, but since we only have one neighbor and one interface this simple approach should work fine.set prefix-list ospf 224.0.0.5/32set prefix-list ospf 224.0.0.6/32set prefix-list ospf 192.168.11.0/30

Navigate to the [edit firewall family inet filter protect-re] hierarchy. Create a term called allow-bgp and ensure that BGP's TCP messages are accepted from any BGP neighbor identified in the prefix list.set term allow-bgp from source-prefix-list bgp-neighborsset term allow-bgp from protocol tcpset term allow-bgp from port bgpset term allow-bgp then accept

Allow-ospf:set term allow-ospf from source-address 192.168.11.0/30set term allow-ospf from destination-prefix-list ospfset term allow-ospf from protocol ospfset term allow-ospf then accept

Create a term called allow-ntp and ensure that NTP's UDP messages are accepted from configured NTP server (172.25.11.254). Need to make sure that NTP related information is accepted from the local loopback address (192.168.31.1) because the system connects to the NTP daemon on the Junos device itself. NTP communication will work fine without the loopback address but will not be able to validate.set term allow-ntp from source-address 172.25.11.254set term allow-ntp from source-address 192.168.31.1set term allow-ntp from protocol udpset term allow-ntp from destination-port ntpset term allow-ntp then accept

Allow-ftp:set term allow-ftp from protocol tcpset term allow-ftp from port ftpset term allow-ftp from port ftp-dataset term allow-ftp then accept

Allow-ssh:set term allow-ssh from protocol tcpset term allow-ssh from port sshset term allow-ssh then accept

Allow-telnet:set term allow-telnet from source-address 172.25.11.254/32set term allow-telnet from protocol tcpset term allow-telnet from destination-port telnetset term allow-telnet then accept

Create a final term named block-rest to discard all other traffic. There is an implicit deny when dealing with firewall filters but we will create the term for others who might review our work.set term block-rest then discard

Apply it as an input filter on the loopback interface. Use commit confirmed with a 5 minute interval to ensure connectivity is not impacted.set interfaces lo0 unit 0 family inet filter input protect-recommit confirmed 5

Performing Interface Troubleshooting:

Issue the show interfaces terse command.Interface Admin Link Proto Local Remotege-0/0/1.0 down up inet 172.18.2.2/30 The logical interface for ge-0/0/1.0 is Admin down Link up. An interface unit that has been disabled will show this status.

Issue the show configuration interfaces ge-0/0/1 command to review the current ge-0/0/1 settings. disable;

Use the show bgp neighbor 172.22.131.37 command to examine the session that is currently in an Active state.Peer: 172.22.131.37 AS 65230 Local: 172.22.131.38 AS 65501 Error: 'Open Message Error' Sent: 6 Recv: 0

Enter into configuration mode and navigate to the [edit protocols bgp] hierarchy and enable traceoptions flagging the normal and open conditions.set traceoptions file bgp-traceset traceoptions flag normalset traceoptions flag open

Review the contents of the new traceoptions file and identify the problem relating the failure to establish a neighborship with EBGP peer.show log bgp-tracebgp_process_open:4059: NOTIFICATION sent to 172.22.131.37 (External AS 65230): code 2 (Open Message Error) subcode 2 (bad peer AS number), Reason: peer 172.22.131.37 (External AS 65230) claims 65530, 65230 configuredThe message indicates that 65230 is configured but the peer is looking for 65530.

Issue the show configuration protocols bgp command to see group_name. Correct the peer AS number that is not configured correctly for the EBGP group by changing the configured peer AS to 65530.set group ebgp-AS65530 peer-as 65530

OSPF hello packets that are sent from a remote router and are destined for the local router.

Telnet traffic that is sent from a remote host and is destined for the local router.

SCP traffic that is destined for router's loopback interface.

SFTP traffic that enters one interface and is destined for a local physical interface.

SFTP traffic that enters and exits the same interface on the local router.

If it is transit traffic, it is not exception traffic:- SCP traffic that enters one interface and exits another interface on a local router.- BGP updates that travel through the local router and are destined for a remote router.- Telnet traffic that travels through the local router and is destined for a remote end host.

Receive an alarm that Junos device is experiencing problems regarding temperature. show chassis temperature-thresholds and show chassis environment commands would use to investigate this problem.

How to verify the component status, temperature, and cooling system:kb.juniper.net/InfoCenter/index?page=content&id=KB10969

show chassis hardware command display a list of all Flexible PIC Concentrators (FPCs) and PICs installed on the router or switch chassis, including the hardware version level and serial number.

After editing to device's configuration, commit command must enter to activate the configuration changes.

edit interfaces command use to navigate to [edit interfaces].

user@router# run show interfaces terse Interface Admin Link Proto Local fe-0/0/0 up upfe-0/0/0.0 up up inet 10.0.39.2/24 iso mpls fe-0/0/1 up upfe-0/0/1.0 up up inet 10.0.18.2/24fe-0/0/1.5 down up inet 10.0.19.2/24 An administrator is unable to ping any address on the 10.0.19.0/24 subnet. To identify the problem, the administrator uses the command shown above. Issue the command delete interfaces fe-0/0/1.5 disable step should be taken to solve the problem.

If you want to back up device's current configuration to an archive site, can configure the router or switch to transfer its currently active configuration by FTP or secure copy (SCP) periodically or after each commit.www.juniper.net/documentation/en_US/junos/topics/task/configuration/junos-software-system-management-router-configuration-archiving.html#jd0e43

The packet is dropped from the network and The system sends an ICMP message back to the source of the packet when using the reject parameter as the next-hop value for a static route.set routing-options static route 10.1.1.1/32 rejectwww.juniper.net/documentation/en_US/junos/topics/reference/general/firewall-filter-actions-terminating.html

[edit policy-options] is hierarchy are routing policies defined.

set policy-options policy-statement <static-routes> term <exportstatic1> from protocol staticset policy-options policy-statement<static-routes> term <exportstatic1> then acceptset protocol ospf export<static-routes> command will apply a policy to redistribute static routes into OSPF.

show route forwarding-table command will display the contents of the forwarding table.

Commands allow to return to a previous version of software on the device:

request system software add <package-name>

request system software rollback

Cisco automatically resolves recursive routes. Those which next hop is not under directly connected interface. But Junos don't behave this way, so have to configure the resolve option.For example, Cisco configures using recursive routes:interface fast 0/0 ip add 3.3.3.1 255.255.255.0ip route 1.1.1.0 255.255.255.0 2.2.2.2ip route 2.2.2.0 255.255.255.0 3.3.3.3Usually, the second static route is some dynamic learned route, this has no sense to configure two recursive statics.

Under Junos this configure will be something like this:set interface fe-0/0/0 unit 0 family inet address 3.3.3.1/24set routing-options static route 1.1.1.0/24 next-hop 2.2.2.2 resolveset routing-options static route 2.2.2.0/24 next-hop 3.3.3.3If you don't use the resolve option, the first static router will be hidden because this has no an active next hop.

Dynamic routing can provide increased network availability when compared to static routing is an advantage of dynamic routing.

110 represents the decimal equivalence of 01101110.

Must segment internal /24 network into a minimum of 12 subnets, each containing a minimum of 12 hosts. /28 network mask use.

> help ?Possible completions: <[Enter]> Execute this command apropos Find help information about a topic reference Reference material syslog System log error messages tip Tip for the day topic Help for high-level topics | Pipe through a command

On the 192.168.1.24/29 network, the minimum host address is 192.168.1.25, and the maximum host address is 192.168.1.30.

When troubleshooting ATM, ping atm vci 0.100 interface at-0/1/0 end-to-end command would allow testing reachability from one side of an ATM cloud to the other.www.juniper.net/documentation/en_US/junos/topics/reference/command-summary/ping-atm.html

There is a network containing 120 routers. Must establish and maintain connectivity between the loopback interfaces of all routers. Because of the critical services using the network, need redundancy and fast failover. OSPF routing protocol should use in this scenario.

Broadcast domains consist of devices that reside on the same VLAN and reachable by frames addressed to the Layer 2 broadcast address.

If a switch is used, the Ethernet collision domain is limited to each device and the switch.

set interfaces ge-0/0/0 unit 0 family inet mtu 1200 command will configure the maximum transmission unit size of an interface.

user@router# show | display set | save /var/tmp/current.conf command uses to save the current candidate configuration in the set format to permanent storage media.

Have been allocated a /22 network. How many usable hosts are available?

/22 = 4 Class C

1 Class C = 256 IP addresses

/22 = 1,024 IP addresses

Usable = 1,022 hosts

On an Ethernet connection, a duplex mismatch is a condition where two connected devices operate in different duplex modes, that is, one operates in half duplex while the other one operates in full duplex.

The primary address on an interface is the address that is used by default as the local address for broadcast and multicast packets sourced locally and sent out the interface. For example, the local address in the packets sent by a ping interface so-0/0/0.0 255.255.255.255 command is the primary address on interface so-0/0/0.0. The primary address flag also can be useful for selecting the local address used for packets sent out unnumbered interfaces when multiple non-127 addresses are configured on the loopback interface, lo0. By default, the primary address on an interface is selected as the numerically lowest local address configured on the interface.www.juniper.net/documentation/en_US/junos/topics/task/configuration/interfaces-configuring-default-primary-and-preferred-addresses-and-interfaces.html> ping interface ge-0/0/1.0 255.255.255.255 PING 255.255.255.255 (255.255.255.255): 56 data bytes64 bytes from 10.0.0.6: icmp_seq=0 ttl=64 time=0.693 msnetworkology.net/2012/03/18/assigning-a-secondary-ip-address-to-an-interface-in-junos